FUEL PUMPS / REGULATOR TECHNICAL INFORMATION

1 Holley offers a wide selection of both mechanical and electric fuel PUMPS fora variety of street performance and race applications. Selecting the properfuel pump for your vehicle, however, begins with understanding your engine sfuel REQUIREMENTST ypically, at wide open throttle, full power, an engine requires lbs. of fuelper horsepower every hour. A gallon of gasoline weighs approximately 6 an engine rated at 350 horsepower will require about 175 pounds(29 gallons) of fuel every hour.(350HP x .5 lbs = 175 lbs of fuel 175 lbs/6 lbs = 29 gallons per hour) fuel PRESSURE AND VOLUMEThe relationship of pressure to volume is inversely proportional.

2 That is, aspressure increases the volume will decrease, everything else being equal. Acertain amount of fuel pressure is always required to maintain engine per-formance by assuring that fuel is available on demand. Also, other factorsand conditions must be taken into account such as acceleration G-forces andfriction within the fuel system itself. At the same time,however, an adequatefuel volume is needed to ensure that the proper amount of fuel can alwaysflow to the engine, especially during peak demand situations. A basic under-standing of this critical pressure/volume relationship is needed when design-ing the proper fuel supply system for your LINE SYSTEMThe fuel line system should be routed to avoid running near hot spots, such asvarious exhaust system components, and designed to promote maximum fuelflow.

3 Most factory stock fuel systems utilize 5/16" fuel lines. This size workswell on street applications with stock engines. When the horsepower require-ments go up, however, the inadequacy of this line size soon becomes appar-ent. A #6 (3/8") line size is sufficient for all street performance applicationsand some racing applications. #8 (1/2") fuel lines are used on everythingelse, including alcohol applications. Avoid using rubber fuel lines, or usethem sparingly, for two reasons. First, rubber is more resistant to the flow offuel than any hard line. An actual pressure loss can be measured over dis-tance.

4 Second, for safety s sake, it s not a good idea to use rubber fuel line,especially when using a high pressure performance fuel LINE FITTINGSLike the fuel line, fuel line fittings are also a very important element in the totalfuel line system and should not be overlooked. Obviously, the fittings shouldbe the same size as the fuel line. Also, if at all possible, you want to mini-mize the use of 90 fittings. Avoid sharp turns or bends in the fuel line rout-ing; these cause undue restrictions to the flow of "3/8"1/2" fuel line sizesFUEL PUMPS / REGULATOR TECHNICAL INFORMATIONMECHANICAL PUMPSV arious Holley mechanical fuel PUMPS are available.

5 110 GPH PUMPS aredesigned for street/strip applications where substantially higher than stock fueldelivery requirements are necessary. 3/8" inlet and outlet ports are utilizedand, with fuel shut-off pressure in the area of 6-1/2 - 8 PSI, a REGULATOR isnot required. 130+ GPH PUMPS are available when maximum fuel delivery isdesirable. 1/2" inlet and outlet ports are included and fuel shut-off pressure isbetween 7-1/2 - 9 PSI. A pressure REGULATOR is definitely required. Both the110 GPH and 130+ GPH PUMPS utilize a high capacity fuel valve design thatwill ensure an adequate fuel supply is always available.

6 ELECTRIC PUMPSH olley offers a complete line of electric in-tank and externally-mounted externally-mounted electric fuel PUMPS are also available in various flowratings. The red pump, P/N 12-801-1, is rated at 97 GPH and it is designedto work with stock or mildly modified engines. Pressure is pre-set to 7 PSI anda REGULATOR is not required. The blue pump, P/N12-802-1, is rated at 110 GPH and it is designed for street/strip applications. Pressure is pre-set at 14 PSIand a REGULATOR is included as part of the package. Neither pump is compatiblewith methanol or alcohol fuels nor should they be used with fuel injection sys-tems.

7 The black pump, P/N 12-815-1, is rated at 140 GPH and is designedto work with either gas or alcohol fuels. This one is similar to the blue pumpbut it kicks out more fuel . These PUMPS all feature a simple, yet rugged, rotorand vane design which has proved itself over the very powerful VOLUMAX PUMPS are available for gasoline or alcoholfuels. They are P/N 12-705-1, rated at 180 GPH and P/N 12-706-1, rated at275 GPH. These feature a gerotor pump design which is extremely efficientand quiet. fuel pressure is pre-set at 15 PSI and both a pressure REGULATOR and3/8" return line to the tank are required.

8 The high volume output of thesepumps make them the natural choice for racers who will settle for nothing butthe best. NOTE:Because of the design of these PUMPS , it is necessary to con-nect both fuel pump inlets to the fuel supply for proper electric in-tank line overs coverage for the most popular Ford, Chrysler,GM and Import applications. Utilizing a proven gerotor design, these pumpsare available in either a 190 or 255 liter per hour (lph) flow PUMPS / REGULATOR TECHNICAL InformationFlow Chart for Externally Mounted Electric fuel PumpsHolleyElectricFuel PumpGroundTo accessoriesOilPressureSwitchCP/N: 12-810 Ignition switchNCNOS tarter motorSolenoidBatteryCoilTodistributorOIL PRESSURE SAFETY SWITCHIt s always a good idea to place a safety switch in the circuit when installingan electric fuel pump.

9 Holley has one available under P/N 12-810. Thisswitch will ensure that the electric pump will not work unless the engine hasoil pressure. It will prevent the pump from running in a situation where themotor may stall with the ignition ON. Wiring the switch through the startersolenoid circuit energizes the pump on engine start-up. After the engine isrunning the switch continues to provide power to the pump as long as there isoil pressure to keep the switch turned on.(SEE ILLUSTRATION) fuel PRESSURE GAUGEST here are a number of places where mechanical fuel pressure gauges couldbe effectively mounted. One place is just before the carburetor.

10 Holleychrome dual feed fuel lines (except model 4500 DOMINATOR) and fuel blocksall have a tapped 1/8 NPT provision for this purpose. Another would be atthe outlet side of the pressure REGULATOR . The Holley four-port Pro-SeriesVOLUMAX REGULATOR incorporates two pressure gauge taps expressly for thispurpose. The electric fuel pressure gauge can be mounted inside the vehicleso that fuel pressure can be monitored while driving. This is possible because,unlike the mechanical gauges, fuel does not flow up to the gauge itself. TheHolley electric gauge, P/N 26-503,utilizes a remote sending unit which is theprimary fuel pressure offers a variety of fuel pressure gauges, depending on use.